Motor comprising a single coil



L. 0. CRENSHAW.

MOTOR COMPRISING A SINGLE COIL.

APPLICATION FILED IIIAYI. I919.

1,361,229, Patented Dec. 7,1920.

. Eve/1hr Los Angeles, count -'UNITED STATES PATENT omen.

LOREN O. CBENSHAW, OF LOS ANGELES, CALIFORNIA, ASSIGNOR. TO MAGNETIC SIGNAL COMPANY, A CORPORATION OF CALIFORNIA.

MOTOR COMPRISING A SINGLE COIL.

Application filed Kay 7,

To all whom it may concern Be it known that I, LOREN O. CRENSHAW, a citizen of the United States residing at of Los Angeles, and State of California, ave invented a new and useful Improvement in Motors Comprising Single Coils, of which the following is a speclfication.

My invention relates to signals which are especially adapted to be placed at railway crossings to warn traflic on the highway of the approach of trains on the railway. It ma of course, be used for other purposes an in other situations.

The rincipal object of my invention is to PIOVlde a signal of great simplicity havin a very smal number of arts and which wil therefore be very relia le.

Referring to the drawings, which are for illustrative purposes only,

Figure 1 is a cross section through the embodiment of my invention.

Fig. 2 is a section on a line 2-2 of Fig. 1.

Fig. 3 is a diagram of connections.

In the form of signal illustrated, a case 11 is provided, having a door 12 suitably secured in the side thereof. A shaft 13 turns free] in bearings 14 formed in the case 11 an projects outside of the case as shown at 15 having a hub 16 rigi'dly secured thereon; a rod 17 secured in the upper portion of hub 16 carries a display 18 which may consist of a target ainted any desirable color-red being pre erred. Secured to the lower portion of hub 16 is a rod 19 carrying a pendulum 2Q, th1s pendulum being of sufiicient weight to hold the parts in their vertical position as shown in Fig. 1, when the signal is not operating. Rigidly secured to the shaft 13 are a pair of castings 25 to which an armature is secured. Secured in the top of the case 11 is a magnet 27 having an ener izing coil 28 wound thereon, the magnet an the armature being so located that they stand in the position shown inv Fig. 1 whenever the signal is not in action. Secured to suitable insulation 30 on one of the castings 25 is a movable contact 31 which is connected through a wire 32 with one terminal of coil 28, the other terminal of which is connected to a wire 33, which passes through a bushing 34in the bottom of the case 11 to an external circuit. Se-

6 cured by insulation 40 on the case 11 is a Specification of Letters Patent.

plane indicated by Patented Dec. 7, 1920. 1919. Serial No. 295,797.

nected through a wire 46 with an external circuit which may contain a battery 47 or other source of power contact making device 48, which may be actuated in any manner-- in the case of a railway signal the contact device 48 is closed by the approach of a train to the crossing.

The method of operation of my invention is as follows:

The parts being in position shown in Fig. l, the contact making device 48 is closed, thus closing the circult through 'the stationary contact finger 43 to the movable contact 31, from thence through coil-28 and the wire 33 to the other sideof the battery 47. Thecoil 28 is thus -energized and tends to pull the armature 26 to the left as viewed in Fig. 1. As soon as the armature is moved a short distance to the left, the set screw 45' strikes upon the casting 41 thus stopping the movement of the contact finger 43 which therefore breaks itscontact with the movable contact 31, opening the circuit of the coil 28 and deenergizing the magnet 27. The pendulum 20 being in" motion at the time the circuit is opened, swings some distance to the left, finally coming to rest .at some position with the pendulum 20 to the right of the vertical line of Fig. 1 and the display 18 to the left. The pendulum then swings back toward the right swinging the movable contact 31 against the stationa contact finger 43 and moving the end of the finger 43 to the right for a short distance during which the coil 28 is again energized, pulling upon and tending to arrest the movement of the armature 26. The momentum given to the armature in its initial movement to the left is first neutralized or compensated for and as soon as it is brought to rest a second impetus is given, again pulling the armature to the left and thus producing a somewhat greater amplitude of swing than the initial swing; this increase in amplitude increases until the entire impetus is absorbed by friction and the signal 18 oscillates between positions A. and B, as

until the circuit is'broken throu h the contact moving device 48, after which the signal settles into its original position so that the signal will be in position to repeat its movement whenever t e contact movement device 48 is again closed.

It will be noted that by using only one coil and one pair of contacts a very simple form of signal is produced.

I claim as my invention:

A motor com rising a pendulum, a shaft from which sai pendulum is dependent, an armature secured to said shaft, a magnet having two limbs located in magnetic relationship to said armature, said magnet being-so placed that it is in a position to atin its lowest position, a coil on one of said limbs, a movable contact secured to but insulated from said armature but connected to energize said coil, a contact finger pivoted on a fixed shaft and so placed as to make contact with said movable contact when the pendulum is in its lowest position, and means. for causing said contact finger to open the circuit with the said contact as said armature approaches its position in the maximum pull.

In testimony whereof I have hereunto set my hand at Los Angeles, California, this 1st day of May, 1919;

LOREN o. CRENSHAW. 

